timing thoughts
08-06-2011, 04:10 PM
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Car: 1989 GTA
Engine: 5.7 /360
Transmission: turbo 350
Axle/Gears: stock
timing thoughts
My "what am I missing" thread completed and car is running. Because nothing is stock on my car where do I set timing? Will 6-8 BTDC get me pretty close(with vacuum advance unhooked)and 18 or so with V/A hooked up?
08-06-2011, 04:21 PM
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: timing thoughts
It's not rocket science....
The engine does not whup out its timing light, read the mark, and think about how it's going to run. All it knows or cares, is when the spark occurs. It can tell this without any instruments at all. So, so can you.
So: loosen the dist bolt until you can just barely turn the dist, but it'll stay put on its own.
Turn it a little bit, making a note of which way you went.
Better or worse?
Better: do it again. Worse: go back to where it was, plus a little more.
Better or worse?
Better: do it again. Worse: go back to where it was, plus a little more.
Et cetera.
Repeat until no further improvement is obtained.
If I may paraphrase one of the Greats in another field:
"If it RUNS good, it IS good".
Resist the temptation to outsmart yourself about "numbers".
Look for crisp, peppy acceleration when stepping on the gas; good gas mileage; low running temp; all of this without pinging EVER. When you get to that point, it's as good as it's going to get.
Once you get there, THEN whup out your timing light and see what the marks say, and write it down; so that any time in the future that some witless clown decides your timing needs "adjusting" for whatever lame-brained reason, you can easily put it back where it belongs.
If you want to do better than that you'll have to get into PROM burning if it's a EFI or other computer-controlled setup; or springs & weights and vacuum can tweeeeking if it's a "traditional" setup.
The engine does not whup out its timing light, read the mark, and think about how it's going to run. All it knows or cares, is when the spark occurs. It can tell this without any instruments at all. So, so can you.
So: loosen the dist bolt until you can just barely turn the dist, but it'll stay put on its own.
Turn it a little bit, making a note of which way you went.
Better or worse?
Better: do it again. Worse: go back to where it was, plus a little more.
Better or worse?
Better: do it again. Worse: go back to where it was, plus a little more.
Et cetera.
Repeat until no further improvement is obtained.
If I may paraphrase one of the Greats in another field:
"If it RUNS good, it IS good".
Resist the temptation to outsmart yourself about "numbers".
Look for crisp, peppy acceleration when stepping on the gas; good gas mileage; low running temp; all of this without pinging EVER. When you get to that point, it's as good as it's going to get.
Once you get there, THEN whup out your timing light and see what the marks say, and write it down; so that any time in the future that some witless clown decides your timing needs "adjusting" for whatever lame-brained reason, you can easily put it back where it belongs.
If you want to do better than that you'll have to get into PROM burning if it's a EFI or other computer-controlled setup; or springs & weights and vacuum can tweeeeking if it's a "traditional" setup.
Last edited by sofakingdom; 08-06-2011 at 04:24 PM.
08-07-2011, 01:58 PM
#3
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Car: 1989 GTA
Engine: 5.7 /360
Transmission: turbo 350
Axle/Gears: stock
Re: timing thoughts
Not real sure about a lot...set the timing so I heard a bit of a lope with my cam(good acceleration off the line) but it is scary quick...from my perspective.The only thing I have to compare it to, is the 71 Duster I had (1974)with a 340 Wedge and was set up to run the 1/8 mile..it was pretty fast.Thanks for all who helped me get this thing running again.
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